Method of assembling a pluralstage axial compressor

ABSTRACT

For assembly of a plural stage axial compressor in which a blade carrier divided into plural parts along an axial plane and provided with a plurality of variable pitch blades is to be assembled to a pitch adjusting sheath, likewise divided into plural parts along an axial plane, with pins on adjusting levers of the blades being engaged in grooves on the inside of the sheath, there is disclosed a method comprising the steps of supporting a separate part of the carrier and a separate part of the sheath coaxially, rotating those separate parts with respect to each other about their common axis to engage the pins on the separate carrier part in the grooves of the separate sheath part, and fastening the separate parts together. There is also disclosed a fixture for use in assembling together such a blade carrier and sheath, this fixture comprising a ring demountable along a diameter into two parts and having two plane, parallel and coaxial annular surfaces, one for support of one blade carrier part and the other for support of one sheath part, and two cylindrical surfaces coaxial with each other and with those annular surfaces, one for centering of the blade carrier part and the other for centering of the sheath part.

United States Patent Original application Jan. 24, 1968, Ser. No. 700,191, new Patent No. 3,538,579. Divided and this application Jan. 21, 1970, Ser. No. 8,121

[54] METHOD OF ASSEMBLING A PLURALSTAGE AXIAL COMPRESSOR 4 Claims, 9 Drawing Figs.

[52] 0.8. CI 29/1564 R, 29/ 156.8 R [51] Int. Cl 323p 15/00 [50} Field ofSearch 29/l56.4 R,

156.8 R, 156.8 FC, 156.8 CF, 200, 200 P, 200 .l,

[56] References Cited UNITED STATES PATENTS 2,501,614 3/1950 Price 415/115' 2,885,768 5/1959 Shinn 3,357,082 12/1967 Beaney 29/1564 R 29/1568 CF ABSTRACT: For assembly of a plural stage axial compressor in which a blade carrier divided into plural parts along an axial plane and provided with a plurality of variable pitch blades is to be assembled to a pitch adjusting sheath, likewise divided into plural parts along an axial plane, with pins on adjusting levers of the blades being engaged in grooves on the inside of the sheath, there is disclosed a method comprising the steps of supporting a separate part of the carrier and a separate part of the sheath coaxially, rotating those separate parts with respect to each other about their common axis to engage the pins on the separate carrier part in the grooves of the separate sheath part, and fastening the separate parts together. There is also disclosed a fixture for use in assembling together such a blade carrier and sheath, this fixture comprising a ring demountable along a diameter into two parts and having two plane, parallel and coaxial annular surfaces, one for support of one blade carrier part and the other for support of one sheath part, and two cylindrical surfaces coaxial with each other and with those annular surfaces, one for centering of the blade carrier part and the other for centering of the sheath part.

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@MW .QQWQ AWN; QWQ W0 QM 3 QM ATTORNEYS METHOD OF ASSEMBLING A PLURALSTAGE AXIAL COMPRESSOR This application is a division of my application Ser. No. 700,191, now US. Pat. No. 3,538,579, filed Jan. 24, 1968.

BACKGROUND OF THE INVENTION Field of the Invention The present invention pertains to a method of assembling a plural-stage axial compressor in which a blade carrier of annular shape, divided into plural parts along an axial plane and supporting a plurality of rotatable guide blades, is coupled to an adjusting sheath of annular shape for the blades, which sheath is similarly divided into plural parts along an axial plane or planes, the pitch adjusting levers of the blades being provided with pegs or pins which are inserted into circular grooves distributed lengthwise of the inner circumference of the sheath.

In plural-stage axial compressors whose guide blades are disposed on a blade carrier and are adjusted in pitch by means of an axially movable sheath, the assembly of the blade carrier to the sheath is difficult and time consuming since the pitch adjusting levers of the individual blades must all be inserted into a circular grooves of the sheath. The method according to the invention makes it possible to simplify the assembly of these parts. In accordance with the invention, one-half of the blade carrier and one-half of the sheath are first supported opposite each other on different diameters of the mounting ring but with their axis coaxial and vertical. These two halves are each of approximately semicylindrical shape, and will for convenience hereinafter sometimes be referred to as shells. Thereafter, the adjusting levers of successive axial rows of guide blades are positioned opposite the corresponding grooves. The cranks or pins of the pitch adjusting levers for each axial row of blades are then inserted into the grooves of the sheath by relative rotation of the two shells with respect to each other about their common axis, and finally the two shells are temporarily fastened together by suitable means for insertion into the compressor housing.

Advantageously, one of the two halves or shells may be fixed to the mounting ring while the other is movable with respect thereto, it being advantageous to rotate the sheath half about the blade carrier half.

The mounting ring of the invention is split along a diameter into, two detachable half rings but which when fastened together form a ring possessing an inner annular support or bearing surface for the blade carrier and a circular centering surface by means of which the blade carrier is centered in the mounting ring. It also includes an exterior annular support surface for support of the sheath, concentric to the inner support surface, and a flange by means of which the adjusting sheath is centered in the mounting ring. At least one of the two supports surfaces takes the form of a race and may be provided with rollers.

In order to facilitate laying down of the two shells after assembly together with their axes vertical, one of the two halves of the split mounting ring may be provided with a straight edge on its exterior.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be further described in terms of a nonlimitative example of the practice of the method thereof and in terms of a nonlimitative exemplary embodiment of the apparatus thereof and by reference to the accompanying drawings, in which:

FIG. 1 illustrates the support of the adjustable pitch guide blades in the blade carrier, FIG. 1 taking the form of a fragmentary section along a plane perpendicular to the axis of the machine; A

FIG. 2 and 3 are respectively plan and side elevational views of the mounting or assembly ring of the invention, FIG. 3 being taken in the direction indicated by the arrow A in FIG. 2 and FIG. 3 moreover being shown partly in section along the section line III-III of FIG. 2;

FIG. 4 shows at an enlarged scale the portion of FIG. 3 within the dash line box B in FIG. 3;

FIG. 5 is a view partly in section and partly in plan of a suspension ring for the blade carrier, affixed thereto at the end of the blade carrier opposite the mounting ring of FIGS. 2 and FIG. 6 is a section taken along the line Vl-VI of FIG. 5;

FIGS. 7 and 8 are plan and side elevational views, FIG. 8 being taken in the direction indicated by the arrow K in FIG. 7, of one means for temporarily fastening to each other a blade carrier half and a sheath half assembled together, preliminary to insertion thereof into the compressor; and

FIG. 9 is a fragmentary perspective view of a plural stage axial compressor in which the assembly of one blade carrier half and of one sheath half is nearly completed.

In FIG. 1, reference character 3 identifies the annular streaming channel provided between the guide blade carrier I and the rotor II of the axial compressor. The blade carrier is made up of two substantially semicylindrical halves or shells, one of which is identified at reference character 1 in FIG. 9. The guide blades 4 of adjustable pitch extend into this channel. One of these blades is illustrated at reference character 4. It is supported in a bore 5 of the .carrier I and is provided with an O -ring disposed in a circular groove in order to seal the flow channel 3 off from the exterior. The O-ring simultaneously serves to protect the bearing of the blade 4 from fouling.

A sleeve 9 is disposed in the bore 5, supported at a shoulder 7 of the bore and fastened to the carrier 1 by screws not shown. Between the shoulder 7 of the bore 5 and the sleeve 9 there is inserted a washer 6 which can vary in thickness from blade to blade. Its function is to permit control of the depth to which the sleeve 9 penetrates into the bore 5 and hence of the depth to which the blade 4 penetrates into the space 3, and thereby of the approach of the blade tip to the rotor II.

An axial bearing ring 8 together with bushings 10 and 1 l at its cylindrical shaft 16. A cover 14 is supported on the sleeve 9 by means of a further axial bearing ring 13, this cover being fastened to the sleeve 9 by means of screw 15. By means of the cover 14 and the screws 15, the rings 8 and 13 and the bushings 10 and 11 and spacer 12 are fastened to the sleeve 9.

Rotation of the blade 4 for variation of pitch is effected by means of the adjusting lever 17 which is supported on a reduced extension 18 of the shaft 16 and which is held thereon he means of a nut 19. The nut is locked by means of a locking wafer 20. At its other end the adjusting lever 17 is provided with a crankpin 21 held in position by means of a locking pin 22. A slide 24 is rotatably engaged about pin 21 with a spacing washer 23 between the slide and the lever. The slide 24 fits into a corresponding groove 50 of the adjustment sheath, as illustrated in FIG. 9.

The mounting ring of the invention is illustrated in FIGS. 2, 3 and 4. It comprises two half rings 25a and 25b which can be fastened to each other to make up a ring generally indicated at 25, for example by means of screws, at flangelike extensions 27 and 28. Each half ring may be cast integrally or made up of a number of parts welded together. The half rings 25a and 25b possess together an inner plane annular support surface 29 for the blade carrier shell 1, spaced from the cylindrical centering surface 30 by means of which the blade carrier shell 1 is centered on the mounting ring 25 in the assembly process.

The outer plane annular support surface 31, 96 is radially outwardly disposed with respect to the inner surface 29 and with respect to the centering surface 30, serves to support one of the two halves or shells 60 of the adjustment sheath, as shown in FIG. 9. The surfaces 29 and 31 are parallel and coaxial. As is 101 particularly illustrated in FIG. 4, the surface 31 has cut therein a circular groove 32 concentric therewith. Bearing rollers 34 supported on pins 33 are distributed around this groove, as illustrated in FIG. 2, and the sheathshell 60 rests thereon. The rollers 34 facilitate shift of the shell 60 with respect to the blade carrier shell 1. At its outer limit the support surface 31 is provided with a flange 35 having a cylindrical inner surface 35a coaxial with the cylindrical surface 30 and with the plane surface 29 and 31, by means of which the sheath shell 60 is held in coaxial position in the mounting ring 25 and with respect to the blade carrier 1.

In order to facilitate laying down into horizontal position of the shells 1 and 60 after their assembly into interengaging relationship while vertical, the half ring 25b is provided at its exterior with a straight edge or foot 36. The other half ring 25a is provided on its exterior with studs 26, as indicated in FIG. 9, by means of which the mounting ring 25 can be handles and transported.

The extension 36 additionally serves to permit disposition horizontally, before assembly into the housing of the compressor, of the halves of the blade carrier and sleeve assembled together in accordance with the invention.

A second positioning or support foot, at the other end of the blade carrier l, is formed by the supporting and adjusting half ring 37 illustrated in FIGS. and 6. This ring, which may also be cast, is provided with bores 38 through which it may be fastened to the blade carrier shell 1 by means of bolts, not shown. The ring 37 additionally includes at the exterior thereof an abutment or supporting surface 40, reinforced by means of three ribs 39. The abutment edge 40 cooperates with the extension 36 on the ring 25 to support the assembly in horizontal position. Additionally, eyes 42 are provided at two flat extensions 41 on the exterior of the ring 37. Through these eyes, the ring 37 and consequently the shells 1 and 60 fastened thereto may be suspended for insertion into the housing of the compressor. The eyes 42 may however be replaced with studs similar to the studs 26 already referred to. Additionally, the ring 37 is provided to the left and to the right of the middle rib 39 with bores 43 through which the upper half of the adjustment sheath can, after assembly to its half of the blade carrier, be clamped between the rings 25b and 37 by means of screws, not shown, for insertion into the compressor housing. The phrase upper half" here is used to refer to the fact that preferably the first pair of shells (one shell I and one shell 60) are assembled together and then inserted into the compressor housing with their concave sides upward, in the lower half of the cavity provided for the blade carrier and sheath in the compressor housing. The second pair of semicylindrical shells, including one shell I and one shell 60, may thus be referred to as the upper shells.

The fastening elements 44 shown in FIGS. 7 and 8, by means of which the first" or lower sheath half or shell 60 and the appurtenant half I of the blade carrier are temporarily fastened to each other for insertion into the compressor housing, cpmp gise in substance a substantially rectangular baseplate 49 provided with four holes45. Through these holes the c ten fifiareta tensd mat s?- si miet x.

means of threaded studs 46 and similarly to the adjustment sheath half 60, near the axial ends thereof (i.e., at the top and bottom thereof in FIG. 9). This is done after the blade carrier half and sheath half have been assembled together and rotated about their common axis so that their limiting axial planes substantially coincide. In this position, two of the holes 45 of each plate 44 accommodate studs 46 of the blade carrier half, and two accommodate bolts which thread into bores 54 of the sheath half. In this way, the lower halves of the blade carrier 1 and sheath 60 are fastened with respect to each other before they are assembled into the housing.

In addition, sleeves or washers 47 are affixed to each plate 49 about the two holes 45 provide for studs 46 from the blade carrier half 1. These sleeves are fitted to the length of the threaded bolts 46 which subsequently serve to fasten together the two halves of the blade carrier. That is, the sleeves 47 are of such length that nuts run down over the threaded parts of studs 46 will serve to hold the plates 49 against the parting plane surface of the blade carrier half I. In addition, each of the plates 49 is provided with a hook 48 at the free side thereof, i.e., on the same side as the sleeves 47. The hooks 48 serve to permit the fastening of cords by means of which the blade carrier and sheath halves may be suspended during assembly. The hooks 48 are so disposed on the plates 49 that the cords contact each other above the center of gravity of the combined halves l and 60. At this contact point the assembled shells I and 60 are suspended for transport. The fastening elements 44 may be cast or made of separate elements welded together.

The adjustment sheath, which is axially split just as is the blade carrier 1 and which is indicated in FIG. 9 may moreover in large machines be divided perpendicularly to its axis as well, is made up of thin sheets or plates reinforced at their ends by means of a ring 53 and by means of flanges 51 and 52 along the parting surfaces thereof. Bores 54 are provided in the flanges 51 which receive fastening bolts upon assembly of the two semicylindrical halves together. In addition, guide rails 55 are fastened to the flanges 51 in order to permit the sheath to move axially of the compressor so as to effect changes in pitch of the guide blades. Motion of the sheath is effected by means of a device such as a servomotor through a linkage, not shown, which engages the blocks 56 fastened to the flanges 5 1.

The groove-bearing rings 50 are welded or otherwise fastened to the inner surface of the sheath. These grooves receive the pins 21 and slides 24 of the pitch changing levers 17 illustrated in FIG. 1. In addition, two collars 57 are fastened to the inner surface of the sheath 60. These collars can rest against corresponding surfaces 58 on the outside of the blade carrier. The collars 57 and the cooperating surfaces 58 serve to support the sheath half 60 and carrier half 1 with respect to each other during assembly so as to prevent stressing of the pins 21 on the levers 17. During operation of the completed compressor a small clearance of the order of 2 mm. exists between the collars 57 and the surfaces 58.

The blade carrier halves are provided with a number of threaded bores 59 at their upper reinforced edges. These bores receive screws for fastening of the supporting and adjusting ring 37 of FIG. 5.

In the embodiment illustrated, assembly of the blade carrier and adjusting sheath is carried out according to the invention in the following manner.

One blade carrier half I is first so fastened to the semiring 25b that when the assembly thereof with one sheath half is later set upright, the blade carrier half will rest on the supporting surface 29 and be centered at the surface 30. Then, the mounting ring 25 is completed by screwing on the second half 25a and the blade supporting half 1 is set upright, with its axis vertical, with the aid of the ring 25. One half 60 of adjustment sheath is then set on the rollers 34 of the other half ring 25a and centered against the surface 350. In the next step the adjustment levers 17 of the blades 4 in one vertical row C (FIG. 9) are so disposed that the slides 24 thereof stand opposite the corresponding grooves 50 of the sheath, as is illustrated for the rows F and G in FIG. 9.

The sheath half 60, which can be readily moved on the rollers 34, is then rotated in the direction of the arrow H in FIG. 9 past the first row C of blades 4. The rows D, E, etc., are then successively set up with insertion of the slides 24 of those rows successively into the grooves 50 upon further rotation of the sheath half 60. Insertion successively of the vertical rows of blade adjustment levers into the grooves 50 continues until the rows F and G are thus inserted. Thereupon the ring 37 is fastened to the blade carrier half I by means of screws entering the tapped holes 59.

Although the process hereinab ove described, for assembly of the lower half of the blade carrier 1 to the lower half of the sheath 60 is the same as that employed in assembling together their upper halves, the fastening of the two halves together occurs differently in the two cases in view of the difference in conditions obtaining in the two cases.

In the case of the lower halves, the fastening takes place by means of the elements 44 illustrated in FIGS. 7 and 8. As hereinabove already briefly stated, the fastening elements 44 are affixed to the planes 51 of the flanges on the sheath half 60 and to the corresponding surfaces along the parting plane of the blade carrier half 1, these surfaces being coplanar with the planes 51 when the lower half of the sheath and lower half of the blade carrier have been fully assembled together. The half ring 25a is then removed. The lower half" assembly, comprising a semicylindrical half of the blade carrier and a semicylindrical half of the sheath, is then set down on the supports 36 and 40 of the half rings 25b and 37, this operation being carried out with the aid of a suitable handling fixture which connects to the ring 37.

After the fixture is connected to the hooks 48 of the fastening means 44, the two half rings 25b and 37 are removed and the lower half of the assembly comprising a blade carrier half 1 and a sheath half 60 is inserted into the compressor housing. The temporary fastening plates 44 may then be removed.

The other two halves, one of the blade carrier and the other of sheath, are then assembled together in substantially the same way, to form the upper half of the complete assembly which when completed will comprise an annular blade carrier inside an annular sheath. Since however the fastening elements 44 would prevent setting of the upper half of the assembly onto the lower half already inserted into the compressor housing, affixation of the upper half of the sheath 60 to the upper half of the carrier 1 is effected by means of the support ring 37, fastened at 38 to the upper half of the carrier whereby the upper half of the sheath 60 is clamped between the rings 25b and 37 by means of screws passing through the threaded bores 43 (FIG. 5). After loosening of the semiring 25a, the assembled upper half of the blade carrier 1 and of the sheath 60 are then set onto the lower half of the assembly in the compressor housing, with the aid of the fixture which connects to the eyes 42 of ring 37 and to the studs 26 of the half ring 25b, whereafter the half rings 25b and 37 may be removed. The two halves 1 of the blade carrier are then assembled together by means of screws 46 and nuts, not shown. To fasten the nuts and screws together the upper half of the sheath 60 is provided with slotted holes, not shown, through which a wrench can be passed. Finally the two halves of the sheath 60 are then fastened together by screws, not shown, passing through the bores 54. 1

While the present invention has been described herein in terms of a presently preferred embodiment of the apparatus thereof and in terms of the presently preferred practice of the method thereof, the invention itself is not limited-thereto but, rather, comprises all modifications on and departures from that embodiment and preferred practice properly falling within the spirit and scope of the appended claims.

I claim l. A method of assembling a plural stage axial compressor in which an annular blade carrier divided into plural parts along an axial plane and provided with a plurality of variable pitch blades is to be assembled to an annular pitch adjusting sheath, likewise divided into plural parts along an axial plane, with pins on adjusting levers of the blades being engaged in grooves on the inside of the sheath, which method comprises supporting a separate part of the carrier and separate part of the sheath coaxially, rotating said separate parts with respect to each other about their common axis to engage the pins on said separate carrier part in the grooves of said separate sheath part, and fastening said separate parts together.

2. A method according to claim 1 including the further step of supporting said separate parts on coaxial circular guide surfaces.

3. A method according to claim 2 including the further step of fastening one of said separate parts with respect to said guide surfaces.

4. A method according to claim 3 wherein said separate carrier part is fastened with respect to said guide surfaces and said separate sheath part is rotated therearound. 

2. A method according to claim 1 including the further step of supporting said separate parts on coaxial circular guide surfaces.
 3. A method according to claim 2 including the further step of fastening one of said separate parts with respect to said guide surfaces.
 4. A method according to claim 3 wherein said separate carrier part is fastened with respect to said guide surfaces and said separate sheath part is rotated therearound. 